This avoids us executing an mfc0 c0_count instruction on processors which
don't have but also on certain R4000 and R4400 versions where reading from
the count register just in the very moment when its value equals
c0_compare will result in the timer interrupt getting lost.

There is still a number of users of get_cycles remaining outside the
arch code:

crypto/tcrypt.c:                start = get_cycles();
crypto/tcrypt.c:                end = get_cycles();
crypto/tcrypt.c:                start = get_cycles();
crypto/tcrypt.c:                end = get_cycles();
crypto/tcrypt.c:                start = get_cycles();
crypto/tcrypt.c:                end = get_cycles();
drivers/char/hangcheck-timer.c: return get_cycles();
drivers/char/hangcheck-timer.c: printk("Hangcheck: Using get_cycles().\n");
drivers/char/random.c:  sample.cycles = get_cycles();
drivers/input/joystick/analog.c:#define GET_TIME(x)     do { x = get_cycles(); }
include/linux/arcdevice.h:          _x = get_cycles(); \
include/linux/arcdevice.h:          _y = get_cycles(); \
mm/slub.c:      if (!s->defrag_ratio || get_cycles() % 1024 > s->defrag_ratio)
mm/slub.c:      p += 64 + (get_cycles() & 0xff) * sizeof(void *);
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

This is the clock rate of the i8253 PIT.  A MIPS system may not have
a PIT by the symbol is used all over the kernel including some APIs.
So keeping it defined to the number for the PIT is the only sane thing
for now.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

* export asm/sgidefs.h
* include asm/isadep.h only if in kernel
* do not export contents of asm/timex.h and asm/user.h
Signed-off-by: NAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!